Retinal Detachment occurs when the retina separates from its normal position against the underlying tissues that support its function. Because the retina depends on its anatomical relationship with these tissues for oxygenation and metabolic support, prolonged separation can cause irreversible photoreceptor and retinal damage. Retinal detachment is an ophthalmic emergency because untreated detachment can progress and permanently impair vision. Several forms exist, with rhegmatogenous retinal detachment being the common form in which a retinal tear or break permits fluid to pass underneath the retina.
Rhegmatogenous Retinal Detachment often develops after changes in the vitreous gel, particularly when the vitreous separates from the retina with age. This process can produce traction on the retina and create a retinal tear. Once a break is present, liquefied vitreous can enter the space beneath the retina and progressively separate it from the underlying tissue. Risk is increased by factors such as significant short-sightedness, previous cataract or other eye surgery, ocular trauma, previous retinal detachment and certain retinal degenerations.
Other forms include tractional retinal detachment and exudative or serous retinal detachment. Tractional detachment occurs when abnormal membranes or fibrous tissue pull the retina away from its supporting structures, and it can occur in advanced diabetic retinopathy and other disorders involving abnormal retinal vascularisation. Exudative detachment occurs when fluid accumulates beneath the retina without a retinal tear, with inflammatory, vascular, neoplastic or other disorders potentially contributing. Distinguishing these mechanisms is important because treatment depends on the cause.
Symptoms can include a sudden increase in floaters, flashes of light and the appearance of a dark curtain, shadow or area of missing vision. A retinal tear can sometimes produce flashes and floaters before a complete detachment occurs. Central vision may remain relatively preserved if the macula is initially unaffected, whereas macular involvement can cause major loss of detailed vision. Symptoms vary according to the location and extent of retinal involvement, so the absence of severe pain does not make retinal detachment harmless.
Diagnosis generally requires a comprehensive ophthalmic examination, often including pupil dilation and detailed examination of the peripheral retina. Indirect ophthalmoscopy can allow the clinician to identify retinal tears or detachment, while ocular ultrasonography can be useful when the view of the retina is obscured, such as by vitreous haemorrhage or dense media opacity. Optical coherence tomography can provide detailed information about the macula but does not replace appropriate peripheral retinal examination when detachment is suspected.
Treatment is usually surgical when a significant retinal detachment is present. Procedures can include pneumatic retinopexy, scleral buckling and pars plana vitrectomy, with the choice determined by the configuration of the detachment, location and number of retinal breaks, lens status, vitreous condition and other clinical factors. Retinal tears without established detachment may sometimes be treated with laser photocoagulation or cryotherapy to create a surrounding adhesion and reduce the risk of progression.
Retinal Detachment is different from posterior vitreous detachment, although the two can be related. Posterior vitreous detachment involves separation of the vitreous from the retina and is common with ageing; it does not automatically mean that the retina has detached. However, vitreous separation can cause retinal tears in some people, and a retinal tear can progress to detachment. New flashes or floaters therefore warrant prompt assessment, particularly when they are sudden or associated with visual-field loss.
The major limitation in preventing retinal detachment is that some retinal tears and detachments develop unpredictably. People with known risk factors may receive closer monitoring, and identified retinal tears can sometimes be treated before detachment occurs. Once detachment is suspected, delaying assessment can allow the affected area to enlarge and may worsen the visual prognosis, particularly if the macula becomes detached. Retinal Detachment therefore illustrates why sudden painless visual symptoms can represent an emergency even when the eye appears externally normal.
